Why are your eyes so red? You _______ have slept well last night.

all ready to put it into operation; __________,we’re going to take action as soon as possible

I’m very tired these days because of walking to school every day.—________ useful exercise you are taking! It can help you keep healthy.

Many people are __________ building a chemical factory（化工厂）near here . They are worrying about the possible pollution .

Who______ it be that is knocking at the door —It ______ be Father, but I’m not sure.